How long do plane blades last?

[bugbear]

Clearly, the blade of a #8, used only for jointing, by an weekend-and-evenings-only worker
will last for centuries.

But how long would the blade of a used-the-most #4 or #5, owned by a 8 hours a day, 5 days
a week, full timer last?

I've never heard of plane blades being a "high turnover" consumable, and most blades
I've seen in s/h planes are quite long. If they were routinely being used up, you'd expect
to see "all possible" blade lengths, so I conclude that most blades are original.

This question is intimately and arithmetically linked with "how often do you sharpen"
and "how much material is removed in a single sharpen".

The latter question, from DW, provoked this post.

BugBear

 

[JimB]

My FIL kept working until he was over eighty. He kept two planes on the go, Record No4s. in the time I knew him he replaced a blade once in about forty years. That blade had very little left on it. I know that's not real evidence but I've seen the same as you, well-worked planes with plenty of meat on what looks like the original blades.

 

[Jacob]

They last for many years even with heavy use. Probably less with over enthusiastic sharpening (all that power grinding).
They do wear out eventually and I've several old woodies where the edge has reached the slot. Previous owners heavy use, not me!
They've become higher turnover items since tool sellers have promoted the stupid idea of having sets of different blades with different bevels.

 

[undergroundhunter]

I recall Paul sellers saying he has replaced a couple in his No4, I'm referring to the one he bought when he started his apprenticeship 50 years ago. As has been said it would most definitely depend on the sharpening method used and the frequency. I bought a type 11 no4 with the original balde (no telling how it was previously used though).

Matt

 

[Bluekingfisher]

I recall Paul sellers saying he has replaced a couple in his No4, I'm referring to the one he bought when he started his apprenticeship 50 years ago. As has been said it would most definitely depend on the sharpening method used and the frequency. I bought a type 11 no4 with the original balde (no telling how it was previously used though).

Matt

It was actually 4 irons he said he has replaced in his 50 year career.

I suspect that figure represents good value for money although he has a stack of #4 planeslined up on his bench and tool cab, so I can only assume he does not use the same one all day everyday.

David

 

[Bluekingfisher]

However to answer the OP's question. I expect the variables are too numerable to offer a realistic response?

Hardness of steel/alloys of the iron, frequency of use, type of work (fine work more sharpening, carpentry tasks less so perhaps) etc are or could be contributing factors to the wear of the iron.

I would agree however, many vintage planes would appear to be fitted with their original irons although what is forgotten with such planes is, just about every red blooded man would have had a tool kit or parts for 'homers' in decades past. Resulting in small infrequent jobs around the house only. I think this is evident as many of the vintage planes I have come across have not been fettled in any way suggesting it has sat on a garage shelf all its life.

David

 

[Beau]

Been through a few myself. One for the No 4 and got a Hock on the 5 1/2 coming to an end as well. The blade on my 9 1/2 is also at it's limit. Not full time any more but guess I do like a bit of sharpening.

 

[ED65]

Interesting question! I suspect the answer is How long is a piece of string? given the innumerable variables.

Although I've seen a few myself and we've all seen pictures, I do think it's odd how few heavily-worn irons I've come across in the flesh, either separated or within an antique plane. During this year's car boot season I saw more planes than typically, including a pair of Stanley-alikes that had obviously seen very hard use in a school, but the irons were not worn down excessively. Whether they were the original irons is impossible to say of course.

At another sale I happened to see a trio of old irons jammed into a single coffin smoother, one iron was worn down close to the slot but the other two were at or close to original length. Beside it was its twin, but this had the double iron still present, and if I recall correctly the cutter was very close to full length. That ratio of one worn iron in four is higher than the average for what I've seen.

 

[bugbear]

...how much comes off of an iron in a typical sharpening? I never used a two piece cap because I figured if it was a couple of thousandths...

If it were as much as the suggested 2 thou, AKA 1/500, the 2" of steel a new blade has below the cap-iron slot would only give you 1000 sharpenings.

On that assumption, in a working year of 250 days, a sharpen-a-day would use up a blade in 4 years.

Which is reductio ad absurdum - we can conclude that sharpening doesn't remove 2 thou, and that Stay Set
cap irons may have benefits in this regard.

BugBear

 

[D_W]

Warren Mickley, who has no power tools, has mentioned replacing the iron (due to wearing it out) in his try plane. I think he does mostly restoration work now, but anyone who can honestly say they have replaced an iron like warren - and in doing so, using only oilstones to sharpen and no grinder - has put in a significant amount of time working.

The most stingy method of sharpening I can think of is to roll a wire edge that is only as large as the situation demands, and with a natural stone of some sort, and then polish it off. I'd bet by using a washita, I'm consuming a third of what I was consuming using modern stones.

And avoid things that chip an iron (like too thin of a bevel).

Interesting in the different plane philosophies that a japanese iron is intended to last several bodies. In the old wooden plane, the plane body is expected to last several irons.

 

[D_W]

One other aspect is experience with consumption, and plane type.

I have two planes that I refer to to get opinion on double iron vs. single iron. One is a try plane that I made, but with an old butcher iron that was NOS. The other is a beautiful JT Brown jointer bedded at 50 degrees and with a very tight mouth, also with a butcher iron (it was unused or close to it when I got it, hard to tell given its age).

More sharpening occurs with the single iron plane than the double iron plane. Probably a factor of two. Kees did a good job of summarizing why that is, but it's a combination of what hogs better vs. what design stays in the cut better.

A more experienced user in either plane type is probably going to take a larger shaving, unless they're just cleaning up machine work. Larger shaving is a two fold increase in edge longevity over a thinner shaving.
1) a plane iron can have poorer clearance with a thick shaving and still work quite well, but instantly stay out of the cut when the shaving is made thinner
2) a thicker shaving lets you remove a larger volume of wood before resharpening

Plus a more experienced user is going to have a regimen that involves no iron chipping because they'll know from experience that early chipping means early resharpening, even if you can tolerate lines in your work.

 

[Vann]

...how long would the blade of a used-the-most #4 or #5, owned by a 8 hours a day, 5 days a week, full timer last?

Even that is very variable. I suspect that your old fashioned worker, at a bench 40 hours a week, would probably only use his No.4 and/or No.5 for 15-30 minutes a day (say 30 seconds - 30 to 60 times in a shift). Maybe a proper galoot, shunning his P/T while preparing his boards by hand, would amass sufficent hours to wear out an iron...?

...most blades I've seen in s/h planes are quite long. If they were routinely being used up, you'd expect to see "all possible" blade lengths, so I conclude that most blades are original.

In my experience of buying too many second hand planes (mostly in the "bottom-feeder" bracket ), I've come across a big variety in lengths. I agree though, that most are near full length/almost unused. The next biggest group are the "approaching the slot" irons - where I suspect I've been palmed-off with the least valuable iron the seller has

I think the single biggest consumer of cutting steel in plane irons these days, is rust.

The school my wife works at, still has a woodwork room. I doubt a single plane still has it's original irons (nor lever-cap :roll: )

Cheers, Vann.

 

[D_W]

...how much comes off of an iron in a typical sharpening? I never used a two piece cap because I figured if it was a couple of thousandths...

If it were as much as the suggested 2 thou, AKA 1/500, the 2" of steel a new blade has below the cap-iron slot would only give you 1000 sharpenings.

On that assumption, in a working year of 250 days, a sharpen-a-day would use up a blade in 4 years.

Which is reductio ad absurdum - we can conclude that sharpening doesn't remove 2 thou, and that Stay Set
cap irons may have benefits in this regard.

BugBear

I don't think my regimen removes 2 thousanths, but I use oilstones and never remove the bevel completely when grinding. It is a lot, but someone using a tormek or some such machine that completely removes a bevel (or a belt grinder or sander) may remove something like that.

For the average amateur, I doubt most will ever sharpen a plane 1000 times. Before I went basically to two wooden planes and two stanley 4s (two only because if you drop one, they break, and I've dropped one to learn that), I bought and sold a lot of planes to try things, and I would guess that at least half of the planes that people said *they were using* still had the primary bevel on them, with just some evidence of a few sharpenings.

I hope that I can wear out an iron or two before I'm room temperature.

 

[Bm101]

They've become higher turnover items since tool sellers have promoted the stupid idea of having sets of different blades with different bevels.

Jacob, can I ask why you don't like it? I only ask as a novice because the QS 62 low angle plane I got second hand from the sale section here has been great for me, a bit of a revelation, and comes with 3 different angle blades. When I started planing and getting tearing i upped the angle of the blade, slowed down and it seemed to work (for me at least in this case, it's on keruing though hardly, elm burr) I also went at the problem areas at 45 odd degrees from both ways across the grain and that seemed to help as well, not sure why I did, just instinct. It doesn't have a chipbreaker btw and the blades were as sharp as I can manage to get them. I'd be interested in what you thought.

Sorry if im diverting from the thread at all. Just wondered why. Thanks.

Cheers
Chris

 

[Racers]

They've become higher turnover items since tool sellers have promoted the stupid idea of having sets of different blades with different bevels.

Jacob, can I ask why you don't like it? I only ask as a novice because the QS 62 low angle plane I got second hand from the sale section here has been great for me, a bit of a revelation, and comes with 3 different angle blades. When I started planing and getting tearing i upped the angle of the blade, slowed down and it seemed to work (for me at least in this case, it's on keruing though hardly, elm burr) I also went at the problem areas at 45 odd degrees from both ways across the grain and that seemed to help as well, not sure why I did, just instinct. It doesn't have a chipbreaker btw and the blades were as sharp as I can manage to get them. I'd be interested in what you thought.

Sorry if im diverting from the thread at all. Just wondered why. Thanks.

Cheers
Chris

Because its "new"

I see no problem with having one plane with several blades straight, cambered etc or several planes each set up differently.

Pete

 

[ED65]

The most stingy method of sharpening I can think of is to roll a wire edge that is only as large as the situation demands, and with a natural stone of some sort, and then polish it off.

My primary "upkeep sharpening" is done by stropping only, I suspect that's the stingiest of any possible option. Obviously you have to be good about not leaving it too long before you take the iron or chisel to the strop or you're not getting a viable edge back.

And avoid things that chip an iron (like too thin of a bevel).

I have two antique irons to re-sharpen soon now that they've had their rust jackets removed and I was planning on taking the opportunity to directly compare performance with honing at 25-30° and at 40°+ respectively. The intention was to see for myself if there is much or any difference in effort needed to take shavings but it can also be used to see if there's any difference in edge durability.

In both cases these will be secondary bevels as I don't want to disturb the original ground bevels, in one case because to remove it would require grinding off nearly 13mm or 1/2" of metal!) which I hope won't have any impact on the validity of the results.

 

[ED65]

Bueller, anyone: I presume it's not common to hone an iron lower than 25°?

 

[D_W]

I've never had luck with a plane below about 30 degrees final bevel. If using a japanese plane (where there's clearance issues) at a 27 or 28 degree primary bevel , and doing so briskly in medium hardwoods, I've never gotten the kind of performance you'd expect from such fine steel. Sacrifice some clearance, and no problem. i think at 27 or 28 degrees, you only get good longevity in defect free softwoods. I put a tiny final bevel on them just higher than 30.

For bench planes, steve elliot did a study on some of the more modern stuff, and for A2 didn't find elimination of chipout until he was at 34 degrees. David Charlesworth promotes a sharpening method at 35 degrees final bevel and it works very well for A2. Using A2 at 30 invites microchipping and longevity suffers, despite much greater clearance.

I've seen a lot of people debate that they do well with a thin bevel angle, but first rule of planing a finished surface AND getting the best edge longevity is to eliminate microchipping. Second to that is getting increased clearance, which also gives you more time between sharpening. The two work against each other.

My opinion from fiddling with all of this is that using A2, you will want to follow steve's advice or you risk using an iron that is harder to sharpen and lasts less well than a high carbon steel iron sharpened properly.

If you move to freehanding, this goes into practice as just learning by experimentation where your habitual hold of an iron gives you both chip resistance and adequate clearance.

A 40 degree final bevel is going to seem like it's coming out of the cut too fast (because dulling reduces clearance, so you're starting at a point where an already partially dulled iron would be in terms of clearance).

if you use a plane below 30 final bevel long enough, you'll encounter little lines all over your work, and not until you eliminate those will you realize that it's affecting edge longevity.

(I don't know where my freehanded irons are, but I'd suspect it's just south of 35 degrees, because my primary is 25 and it's a fair bit steeper than that - i just know from experience that they don't chip based on how I hold them to hone, no matter the alloy).

You may find old carpenters literature from stanley that suggests 25 degrees, but presume that's for carpentry and not cabinetmaking.

 

[bugbear]

You may find old carpenters literature from stanley that suggests 25 degrees, but presume that's for carpentry and not cabinetmaking.

I've never seen that - any examples?

Most texts, from both instructors and manufacturers is pretty much 25 primary, 30 secondary.

I suppose plough iron blades are an exception, where Stanley and Record both recommend 35, single bevel.

That's about it.

BugBear

 

[D_W]

You may find old carpenters literature from stanley that suggests 25 degrees, but presume that's for carpentry and not cabinetmaking.

I've never seen that - any examples?

Most texts, from both instructors and manufacturers is pretty much 25 primary, 30 secondary.

I suppose plough iron blades are an exception, where Stanley and Record both recommend 35, single bevel.

That's about it.

BugBear

No, I've got no source for that. I had a stanley block plane blade or plane (can't remember which) where the back of the package said to grind 25-30 and hone 30-35.

I'm recalling 25 degrees as something someone mentioned on a forum, but that doesn't mean it was ever printed. I may also be remembering that stanley has provided irons with 25 degree bevels and with 30 degree bevels. The later ones have a recommendation on the blade, right (I don't have much "later" hardware). Anyone know what grind angle was written on the irons?